As rapid advance in information and electro-optical industry, electronic products have been largely upgraded and thinned in the recent years. Under the requirements of high speed, high frequency, and miniaturization, the density of heating of the electronic elements is higher and higher, so heat dissipation efficiency has become one of the key factors to determine the stability of electronic products. Since both heat pipes and heat conducting fins have high heat conductivity, they are widely used to dissipate heat in various electronic products. Both heat pipes and heat conducting fins dissipate heat mainly through a wick structure made of a vacuum copper pipe or a copper sheet provided on an inclosed inner wall of a chamber thereof by sintering. Heat produced by electronic elements, such as central processing units (CPUs), and the like is absorbed by an evaporation section corresponding to a working fluid provided in the copper pipe and then evaporated. Thereafter, the evaporated heat is dissipated via a condensing section, such as heat radiation fins or fans, and condensed into liquid due to capillary force, then flowed back to the evaporation section to complete the whole inclosed circulation.
A prior heat spreader is disclosed and includes a base. The base has a first and a second side opposite to the first side, on which an S-shaped groove is provided for an S-shaped heat pipe to be located therein. The first side of the base has a plurality of cooling fins and at least one U-shaped groove, which has one opening toward one opening of the S-shaped groove to secure the opening of the S-shaped groove. The heat spreader further includes at least one U-shaped heat pipe, which is correspondingly located in the U-shaped groove of the first side of the base. Therefore, heat accumulated in the base can be quickly transferred circumferentially from a center of the base to a periphery of the base. However, it is hard to control the S-shaped and the U-shaped groove depth and apt to cause tolerance problem. Also, when being processing, it is also apt to cause a poor levelness on a back side of the base due to releasing stress, such that the S-shaped and the U-shaped groove respectively have a top and a bottom side that are unlikely to tightly contact with the cooling fins or heat-generating elements, such as central processing units (CPUs) or graphics processing units (GPU). In addition, since the base is made of copper, it has a heavy weight.
In brief, the conventional heat dissipation device has the following disadvantages: (1) being heavy weight; (2) wasting materials; (3) having tolerance problem in groove; and (4) having a poor levelness on a bottom side of the base.
It is therefore tried by the inventor to develop an improved heat dissipation device to overcome the problems of the conventional heat dissipation device.